Digital cameras have been developed based on film based cameras. Digital cameras are based on optical lens systems that operate based on basic laws of optics. For instance, the lens system has a particular field of view that generally depends on the focal length of the lens system. The field of view desired by a user depends on the situation and preferences of the user. In-door pictures are often taken with broader field of view in order to fit proximate subjects in a common picture. Zooming in with a zoom lens or replacing a lens to one with higher focal length is used to enlarge the subject of an image, particularly when photographing distant objects or when willing to emphasize a particular detail of the subject. The zoom lens normally works such that different lenses are mounted on different cylindrical parts that are distanced or approached with respect to each other to change to focal length of the lens.
In film cameras, the aspect ratio of pictures depended on the form of one film exposure ratio. However, the aspect ratio has been changed in post processing by cropping taken pictures to desired aspect form. With digital cameras, aspect ratio is changed in some models by cropping an image either when recording the image or after the image is taken.